JPH09112677A - Hydraulic control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control means for automatic transmission, which can put a friction clutch device in engagement even when the control device goes in failure so that the running condition can be continued. SOLUTION: A primary pressure regulating valve 1 moves with the oil pressure fed through a control pressure passage 12 and regulates the line pressure in a line pressure passage 13. A solenoid valve 5 controls precisely the oil pressure in a command pressure passage 15 from a low level to a maximum oil pressure in the output passage 14 as max. command pressure. The first selector valve 7 puts the control passage in selective communication with the command pressure passage 15 or output passage 14 depending upon the level of oil pressure in a changeover passage 16. When the solenoid valve 5 goes in failure, the changeover passage 16 is put in a low pressure by closing the solenoid valve 6, and the first selector valve 7 selects the output passage 14. The oil pressure in the line pressure passage 13 becomes equal to the max. pressure of R-range substantially because the max. command pressure in the output passage 14 is applied to the primary pressure regulating valve 1, so that clutches and brakes are engaged with no slippage generated even in case the solenoid valve 5 goes in failure, and it is possible for the car to run safely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for an automatic transmission, which hydraulically controls a speed change mechanism of the automatic transmission.

[0002]

2. Description of the Related Art Conventionally, automatic transmissions, which are often used for vehicles and the like, switch a hydraulic pressure applied to each friction engagement device by a hydraulic valve in order to smoothly transmit a rotational driving force according to a load. Gearshift control. Shift control is performed by an occupant's manual operation using a select lever that selects forward, neutral, or reverse, and an automatic transmission control computer based on the engine throttle opening (hereinafter, "automatic transmission control computer" is referred to as ECU). Thus, the automatic gear shift is performed to determine the engaged and disengaged states of the friction engagement device so that the gear ratio becomes appropriate.

As such an automatic transmission hydraulic control device, a command pressure (control hydraulic pressure) applied from a control valve (a solenoid valve in Japanese Patent Laid-Open No. 5-319146) is disclosed in Japanese Patent Laid-Open No. 5-319146. ) Is used to change the line pressure generated by a pressure regulating valve (line pressure control valve in Japanese Patent Laid-Open No. 5-319146).

[0004]

However, in such a conventional hydraulic control device, since the command pressure is directly applied from the control valve that generates the command pressure to the pressure regulating valve, the command pressure becomes low when the control valve is abnormal. As a result, the line pressure generated by the pressure regulating valve decreases, and the clutch slips, so that the vehicle cannot run.

The present invention has been made to solve such a problem, and even when the hydraulic control device is out of order, the friction engagement device can be engaged, and the hydraulic control for an automatic transmission can be ensured in a running state. The purpose is to provide a device.

[0006]

According to the hydraulic control device for an automatic transmission according to claim 1 of the present invention, the line pressure applied to the plurality of friction engagement devices is substantially maximum depending on the failure state of the hydraulic control device. The friction engagement device can be engaged even when the hydraulic control device fails.

According to the hydraulic control device for an automatic transmission according to claim 2 of the present invention, by providing the lockup releasing means for releasing the lockup state in the lockup device according to the failure state of the hydraulic control device, It is possible to prevent engine stop. According to the hydraulic control device for an automatic transmission according to claim 3 of the present invention, a hydraulic control valve for generating a normal command pressure for setting the line pressure, a pressure control valve for generating a line pressure according to the normal command pressure, The pressure control valve includes a first switching valve that switches between a maximum command pressure for causing the pressure control valve to generate an almost maximum value of the line pressure and a normal command pressure and applies the pressure control valve to the pressure control valve. With this configuration, when the hydraulic control valve is abnormal, the first switching valve can select the maximum command pressure, so that the friction engagement device can be engaged even when the hydraulic control valve is abnormal.

According to the hydraulic control device for an automatic transmission according to claim 4 of the present invention, the line pressure generated by the pressure regulating valve can be highly accurately configured by using the hydraulic control valve as a three-way solenoid valve capable of duty control. Can be adjusted. According to the hydraulic control device for an automatic transmission of the fifth aspect of the present invention, by using a two-way solenoid valve as the second switching valve, it is possible to reduce the size and cost of the second switching valve.

According to the hydraulic control apparatus for an automatic transmission according to claim 6 of the present invention, when the second switching valve is abnormal, the second switching valve switches the first switching valve to either high pressure or low pressure. By fixing to one side, the first switching valve selects the maximum command pressure. As a result, the line pressure generated by the pressure regulating valve becomes almost the maximum pressure, so that the friction engagement device can be engaged even when the second switching valve fails.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a system configuration in which the hydraulic control device for an automatic transmission according to the embodiment of the present invention is applied to an automatic transmission for a vehicle (hereinafter, “automatic transmission” is referred to as an AT). The AT transmits the torque generated by the engine to the variable-speed drive via a fluid transmission device such as a torque converter.
The speed is shifted by a plurality of planetary gear devices in the speed change drive device and output.

As is well known, the operation of the vehicle AT automatically or manually switches the gear connection in transmission 300, and the rotational force from an engine (not shown) connected to torque converter 200 is applied to the rear wheels or front wheels of the vehicle. Is transmitted. The automatic speed change means 90 and its peripheral devices are entirely inside an oil pan (not shown) inside the AT below the transmission 300, and a hydraulic control device 4 inside the oil pan is provided.
The area around 00 is the drain of the hydraulic circuit.

The transmission 300 is provided with a known hydraulic pump 56 which is directly connected to the rotating shaft of the engine and is driven to rotate. The driving oil discharged from each hydraulic device to an oil pan or the like is supplied from an intake port 57. The pressure oil is supplied to each device via the line pressure control means 64 by suction. The pressure oil from the hydraulic pump 56 is a high pump oil pressure that fluctuates, is controlled to a constant high line pressure by the line pressure control means 64, and is supplied to each hydraulic device. Each of the friction engagement devices is connected to a gear constituting each speed ratio, such as a planetary gear (not shown), in the transmission 300, and the speed ratio is switched by engaging or disengaging these friction engagement devices. Gear shift control. The lock-up control means 65 adjusts the hydraulic pressure applied to the L / U (lock-up device).

The circuit configuration of the line pressure control means 64 is shown in FIG. The line pressure control means 64 includes a primary pressure regulating valve 1 as a pressure regulating valve that generates a line pressure, a solenoid valve 5 that applies a command pressure to the primary pressure regulating valve 1, and a pressure reducing valve that sets the hydraulic pressure in the output passage 14 to a predetermined pressure or less. 3 and primary pressure regulator 1
And a solenoid valve 6 as a second switching valve that sets the operating hydraulic pressure for switching the first switching valve 7 to high pressure or low pressure.

The position of the primary pressure regulating valve 1 is determined by the balance between the total force of the hydraulic pressure of the control passage 12 and the urging force of the spring 2 and the force of the hydraulic pressure of the line pressure passage 13. The line pressure of the line pressure passage 13 is determined by the balance of forces. As shown in FIG. 3, the hydraulic pressure in the line pressure passage 13 increases as the hydraulic pressure (command pressure) in the control passage 12 increases. The primary pressure regulating valve 1 and a secondary pressure regulating valve (not shown) are connected by an oil passage, and the secondary pressure regulating valve generates the source pressure of the working hydraulic pressure applied to the lockup device.

The position of the pressure reducing valve 3 is determined by the balance between the force received from the hydraulic pressure in the output passage 14 and the urging force of the spring 4, and the pressure in the output passage 14 is kept below a predetermined pressure. The solenoid valve 5 is a duty-controllable three-way solenoid valve, and by performing duty control according to the throttle opening and the shift range, the hydraulic pressure in the command pressure passage 15, which is the normal command pressure, is from the low pressure to the maximum command pressure. The oil pressure in the output passage 14 is also controlled with high accuracy. The hydraulic pressure in the command pressure passage 15 increases as the throttle opening increases, and is controlled so that the reverse range (R range) has a higher maximum value than the forward range (D, 3, 2, 1 range). To be done.

The solenoid valve 6 is a two-way solenoid valve. When the coil (not shown) is energized and opened, the switching passage 16 is opened.
Oil pressure becomes high. When the coil is de-energized, it is closed by the urging force of a spring (not shown) and the switching passage 1
The hydraulic pressure of 6 becomes low pressure. The first switching valve 7 has a switching passage 16
The control passage 12 is selectively communicated with the command pressure passage 15 or the output passage 14 depending on the level of the hydraulic pressure. When the hydraulic pressure in the switching passage 16 is high, the control passage 12 communicates with the command pressure passage 15, and when the hydraulic pressure in the switching passage 16 is low, the control passage 12 communicates with the output passage 14. In the present invention, by changing the configuration of the first switching valve, the control passage 12 communicates with the command pressure passage 15 when the hydraulic pressure in the switching passage 16 is low, and the switching passage 16
It is also possible to make the control passage 12 communicate with the output passage 14 when the hydraulic pressure is high.

Next, the operation of the line pressure control means 64 will be described. (1) When the solenoid valve 5 is normal, the solenoid valve 6 is open and the switching passage 16 has a high pressure, so that the first switching valve 7 is in the position shown in FIG. 1 against the biasing force of the spring 8. Therefore, the command pressure passage 15 and the control passage 12 communicate with each other. Therefore, the solenoid valve 5 duty-controls the hydraulic pressure of the command pressure passage 15,
By applying the oil pressure corresponding to the throttle opening and the shift range to the primary pressure regulating valve 1 via the control passage 12, the oil pressure in the line pressure passage 13 can be set as shown in FIG. That is, the line pressure in the line pressure passage 13 increases in proportion to the command pressure.

(2) When the hydraulic control device fails, such as when the solenoid valve 5 is locked on the low pressure side due to the inclusion of foreign matter or the like, this failure state is detected by detection means (not shown) and a detection signal is sent to the ECU. By doing so, the ECU controls the power supply to the solenoid valve 6 to be off by this detection signal. By closing the solenoid valve 6, the switching passage 16 becomes a low pressure, and the first switching valve 7 moves to the left from the position shown in FIG. 1 by the biasing force of the spring 8, so that the output passage 14 and the control passage 12 are separated from each other. Communicate. Since the hydraulic pressure in the output passage 14 is substantially equal to the maximum value of the command pressure generated by the solenoid valve 5 in the command pressure passage 15, the hydraulic pressure in the line pressure passage 13 is in the R range due to the maximum command pressure applied to the primary pressure regulating valve 1 from the control passage 12. Is almost equal to the maximum pressure of. Therefore, even when the electromagnetic valve 5 is abnormal, the clutch and the brake as the friction engagement device are engaged without slipping, and the vehicle can travel safely.

(3) When the solenoid valve 6 fails, the solenoid valve 6
Since the solenoid valve 6 is closed by the urging force of the spring housed in the control valve 16 and the hydraulic pressure in the switching passage 16 becomes low, the control valve 12 is controlled by the first switching valve 7 regardless of whether the solenoid valve 5 is normal or defective.
And the output passage 14 communicate with each other. Accordingly, even when the solenoid valve 6 fails, the primary pressure regulating valve 1 generates the maximum value of the line pressure, so that the clutch and the brake are engaged without slipping and the vehicle can travel safely.

Next, the line pressure control means 64, the torque converter 200 of the automatic transmission, and the lockup control means 65.
FIG. 4 shows a circuit configuration in which and are combined. Third switching valve 2
The first, fourth switching valve 23, and fifth switching valve 24 constitute lockup releasing means. The switching passage 16 is connected to the third switching valve 21 so as to switch the third switching valve 21 to the right in FIG. When the pressure in the switching passage 16 becomes low when the hydraulic control device fails, the third switching valve 21 moves to the left from the position shown in FIG. 4, and the pressure supply passage 22 communicates with the drain passage 25. Move to the left from the position shown in
The pressure supply passage 26 communicates with the drain passage 27. Then, the fifth switching valve 24 is fixed at the position shown in FIG. 4 by the urging force of the spring 28, so that the lockup clutch 30 as a lockup device is released and the lockup prohibition state is set. Therefore, even when the hydraulic control device is out of order, the lockup can be prohibited at all times, so that the traveling state can be secured without stopping the engine.

Further, the circuit configuration shown in FIG. 4 has a manual switching valve 80, an automatic transmission means 90 and a transmission 30.
A circuit configuration in which 0s are combined is shown in FIG. In the configuration shown in FIG. 5, the clutch 101 of the transmission 300,
The solenoid valve 6 can be shared and the number of parts can be reduced by using the hydraulic pressure of the switching passage 16 as the operating hydraulic pressure of the sixth switching valve 120 that switches the hydraulic pressures applied to the brake valves 103, 104, 106 and the brakes 102, 105. Since the solenoid valve 6 is normally open, the hydraulic pressure in the pressure supply passage 125 is high, and the sixth switching valve 120 is in the position shown in FIG. At this time, when the neutral range (N range, P range) is selected, the line pressure is applied to the solenoid valves 107 to 112 via the sixth switching valve 120. If a duty-controllable three-way solenoid valve is used as the solenoid valves 107 to 112, the hydraulic pressure applied to all the clutches and brakes can be smoothly reduced, so that the shock generated by the range switching to the neutral range can be reduced.

When the hydraulic control device fails, the solenoid valve 6
Is closed and the pressure supply passage 125 becomes low pressure, the switching valve 120 moves to the right from the position shown in FIG. 5 and the pressure supply passages 113 to 118 communicate with the drain passage 124 in the neutral range. Therefore, it is safe even when the hydraulic control device fails without engaging the clutch and brake.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram showing a line pressure control means according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a system configuration of the automatic transmission according to the embodiment.

FIG. 3 is a characteristic diagram showing a relationship between a command pressure and a line pressure according to the present embodiment.

FIG. 4 is a schematic circuit diagram in which a line pressure control means, a torque converter, and a lockup control means of this embodiment are combined.

FIG. 5 is a schematic circuit diagram showing an automatic transmission of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary pressure regulating valve (pressure regulating valve) 3 Pressure reducing valve 5 Hydraulic control valve 6 Solenoid valve (second switching valve) 7 First switching valve 30 Lock-up clutch (lock-up device) 80 Manual switching valve 90 Automatic transmission means 200 Torque converter 300 Transmission 400 Hydraulic control device 500 Select lever

Claims (6)

[Claims] 1. An automatic gear shift control for switching a plurality of gear stages by switching hydraulic pressures applied to a plurality of friction engagement devices provided in an automatic transmission and engaging or disengaging the plurality of friction engagement devices, respectively. A machine hydraulic control device, comprising: line pressure control means for controlling a line pressure for engaging the plurality of friction engagement devices; detection means for detecting a failure state of the hydraulic control device; A hydraulic control device for an automatic transmission, comprising: switching means capable of switching the line pressure applied to the plurality of friction engagement devices to a substantially maximum value by a control signal. 2. A lock-up device provided with a torque converter and a lock-up device provided together with the torque converter, wherein the lock-up device is provided with a lock-up releasing device capable of releasing a lock-up state by a control signal of the detecting device. The hydraulic control device for an automatic transmission according to claim 1. 3. The line pressure control means has a hydraulic control valve for generating a normal command pressure for setting the line pressure and a pressure regulating valve for generating a line pressure according to the normal command pressure, and the switching means. Is a first switching valve which switches between the maximum command pressure for causing the pressure regulating valve to generate a substantially maximum value of the line pressure generated by the pressure regulating valve and the normal command pressure, and which is applied to the pressure regulating valve.
A second switching valve for switching the operating hydraulic pressure for switching the first switching valve to a high pressure or a low pressure, and when the hydraulic control valve is normal, the first switching valve selects the normal command pressure, and the hydraulic control valve The hydraulic control device for an automatic transmission according to claim 1 or 2, wherein the first switching valve selects the maximum command pressure when the abnormality occurs. 4. The hydraulic control device for an automatic transmission according to claim 3, wherein the hydraulic control valve is a three-way solenoid valve capable of duty control. 5. The hydraulic control device for an automatic transmission according to claim 3, wherein the second switching valve is a two-way solenoid valve. 6. When the second switching valve is in an abnormal state, the second switching valve fixes the hydraulic pressure for switching the first switching valve to either high pressure or low pressure so that the first switching valve operates. The hydraulic control device for an automatic transmission according to claim 3, 4 or 5, wherein the maximum command pressure is selected.